Question 3. (3 pts.) Here are two initial boundary value problems in which (f(x), F(t) and S(x) are known functions.. In each case, circle all the non-homogeneities, including any conditions that have to be dealt with in order to use separation of variables. (a) u/au/dx + F(t): x=0.1;u=0; =0, u = f(x), du/dt=0. (b) du/dau/ax + S(x,y): x = 0, u 1; x 1,u-0 -0, u= 0.